The present invention relates generally to systems for administering fluids to the human body, and more particularly to an improved manually-operable pressure pump for use in such systems.
During the infusion of fluids such as blood into the human body it is frequently desirable that the flow rate of the fluid be temporarily increased beyond its normal gravity flow rate. This is particularly so in emergency situations wherein large quantities of fluid must be infused in a short period of time. Such increased flow rates are most conveniently obtained by means of a hand pump disposed in the flow path of the administration set being used to transport fluid into the vein or artery. As conditions require, the attending physician or technician manually actuates the hand pump, causing a quantity of fluid to be infused with each such actuation.
Hand operated pumps heretofore provided in fluid administration sets have not provided entirely satisfactory operation in that they have been difficult to purge of air or other separated gases which may accumulate and coalesce within the pump chamber. Such gases not only decrease the capacity of the pump, but also increase the danger that an air embolus may be accidentally infused into the patient. Both the ball-type and diaphragm-type check valves commonly used in prior art pumps allowed the pumps to be purged only with great difficulty by deforming the housing of the valve and forcing the ball or diaphragm valve away from its valve seat so as to establish an air path to the reservoir. This operation required the expenditure of much time and care on the part of medical personnel. Furthermore, such prior art ball- and diaphragm-type check valves did not allow completely free passage of the fluid in gravity-feed situations since they included no provision for being conditioned to a completely open state.
Accordingly, it is a general object of the present invention to provide a new and improved pressure pump for use in a fluid infusion system.
It is another object of the present invention to provide a new and improved pressure pump from which air and other separated gases can be more easily purged.
It is another object of the present invention to provide a new and improved manually-operated pump for use in a fluid infusion system which includes a valve which can be conditioned to a purge position wherein air trapped within the pump can be purged, or to a pump position wherein fluid can be forced down line into the body.
It is another object of the present invention to provide a manually-operated pump having a user-conditionable valve which automatically protects against inadvertent misconditioning by the user.
It is another object of the present invention to provide an in line manually actuated pump for a fluid infusion system which can be conditioned to provide no hindrance to the free flow of fluid through the system.